GPs can be reassured they are unlikely to have missed serious gastrointestinal disease when making a diagnosis of irritable bowel syndrome, according to Nottingham University researchers who found patients were generally at no increased risk of colorectal cancer in the long term.
The team report in the journal PLoS ONE that they looked at 112,854 cases of irritable bowel syndrome (IBS) identified within the UK Clinical Practice Research Dataset, matched with 546,903 patients with no IBS.
Over follow-up lasting between five and 15 years, 395 of the IBS cases were diagnosed with coeliac disease, compared with 299 of the control patients, while 1,184 IBS patients were diagnosed with irritable bowel disease compared with 569 control patients, and 708 IBS compared with 1,148 controls were diagnosed with colorectal cancer.
Fifteen years after IBS diagnosis, there was a 2% absolute cumulative excess incidence of coeliac disease, irritable bowel disease and colorectal cancer in the IBS group compared with the control group, at 3.7% compared with 1.7%, respectively.
However, for all three conditions, the excess peaked in the first six months, which the authors said ‘suggests that much of the excess incidence of organic gastrointestinal disease occurs during the diagnostic work-up’, where the IBS diagnosis was made as part of the clinical pathway to a final diagnosis.
For colorectal cancer specifically, there was an overall 64% relative increase in the incidence in the first year post-IBS diagnosis, but thereafter the increase fell away and was no longer significant.
The researchers said their findings ‘provide reassurance that non-specialists, especially in primary care, who see most people diagnosed with IBS, are unlikely to be missing an organic condition in the majority of their patients’.
They add that ‘the current guidelines suggesting avoidance of universal referral for these patients is appropriate’.